The Energy Networks Association said on Saturday evening that 259,000 customers were still without power across England, Scotland and Wales, with work to restore supplies ongoing overnight.
Northern Ireland Electricity Networks said more than 15,000 properties were without power on Saturday evening and warned it may take days for supplies to be fully restored. At the storm’s peak, more than 95,000 premises were affected.
Disruption to train travel is also set to continue on Sunday, with National Rail, external warning passengers to check their journeys before travelling.
It said there is likely to be “significant disruption” to services in south-west Scotland, north and south-west England and Wales.
Several operators were reporting problems on Sunday morning, including power lines damaged by downed trees. Speed restrictions are in place on some routes.
The M48 at Severn Bridge between England and Wales is expected to be closed until midday, according to National Highways.
Asked about the government’s response to the storm, Deputy Prime Minister Angela Rayner told the BBC Sunday with Laura Kuenssberg programme: “We saw two people have lost their lives and there has been major disruption.
“I know the energy secretary has been speaking about the power cuts and has been making sure that people have the power, and my thoughts are with those who have had that disruption.”